'soot-stained' originates from Modern English, formed by combining the noun 'soot' and the past participle 'stained' (from the verb 'stain'). 'soot' originally referred to the fine black residue from combustion, and 'stain' is the past participle form indicating something has been marked or discolored.

'soot' comes from Old English 'sōt' meaning 'soot' or 'sootiness'; 'stain' comes into English via Middle English 'stainen' (from Old Norse influence) and the past participle became 'stained'. These elements combined in Modern English to form the compound adjective 'soot-stained'.

Initially, the components meant 'black residue from burning' and 'to mark or discolor'; combined, they have long meant 'marked or blackened by soot', a meaning that has remained stable.